Biological and chemical detector technology has become ever more important over the last several years and, as a result, has been undergoing dramatic growth. This growth is primarily fueled by the need for fast, highly sensitive and highly specific detector systems that would reduce false alarm rates and increase the ability to detect and identify chemical and biological species, such as chemical and biological warfare agents, in a wide range of environments. Currently, the majority of commercially-available chemical and biological agent detection systems rely on separate components or devices for sample collection, separation, and analysis. Thus, operation of such systems often requires multiple manual steps to accomplish, for example, sample preparation and loading, tag and assay handling, fluids recharging, results characterization, etc. None of the commercially available traditional chemical/biological detection systems provides a truly portable integrated unit capable of fully automated detection of multiple chemical or biological agents in a wide range of environments.
In an attempt to better integrate the separate components of chemical and biological detection systems, and to reduce the size of such systems, more recent efforts have focused on microfluidics-based detection systems. These more recent systems are advantageous in that they are useful in a wide range of detection applications and are conceptually similar to well-understood traditional lab analysis techniques. One such effort, known as the LabChip® system produced by Caliper Technologies, uses chips having small channels, e.g., from 5 micrometers to 50 micrometers, to control the flow of samples across a surface for analysis. The chips in the Caliper Technologies system are inserted into the LabChip® system, which includes multiple components for containing reagents and software for controlling experiments and displaying results. The LabChip® system reduces the number of manual steps, thus reducing human error, and requires very small levels of reagent to operate. Once a researcher introduced the samples to the chip, e.g., via pipette, the samples were routed via the microchannels to sampling locations on the chip and analyzed by other components in the system.
Another recent attempt, known as the LILLIPUT chip which is used, for example, with microparts Corporation microspectrometer, uses microchannels linked to a large number of sampling wells in a very small package. Once again, after pipette samples are introduced onto the chip, the samples are routed to the appropriate sampling well via microchannel. As in the LabChip® system, other components are used to analyze the samples and display the results of the analysis.
In yet another attempt, known as the NanoChip™ system by Nanogen Corporation, samples are electrically directed along the surface of a chip to one of a number of test sites. Specifically, since most samples have a natural electrical charge, the samples in the NanoChip™ system can be attracted to a particular test site by creating an opposite charge at that test site. Thus, for example, once a negatively-charged sample is introduced into the NanoChip™ system, e.g., via pipette, that sample can be directed to one or more positively charged test sites.